Canker Sores on Tonsils: Uncommon Location, Differential Diagnosis

Canker sores (aphthous ulcers) rarely occur on the tonsils. They typically affect non-keratinized mucosa: buccal/labial mucosa, ventral tongue, floor of mouth, soft palate.

If You See a Lesion on the Tonsil, Consider:

• Tonsillitis (viral/bacterial): Exudate, erythema, fever.
• Strep throat: Purulent exudate, anterior cervical adenopathy.
• Peritonsillar abscess: Unilateral swelling, trismus, deviation of uvula.
• Oral thrush: White plaques on tonsils, buccal mucosa; scrapable.
• Herpetic lesions: Vesicles → ulcers; HSV-1 or HSV-2.
• Tonsilolith (tonsil stone): Whitish calcified debris in crypts.
• Malignancy: Persistent unilateral lesion, otalgia, weight loss (rare but serious).

Action

Any tonsillar lesion persisting >2 weeks, or accompanied by systemic symptoms, requires ENT evaluation for accurate diagnosis and management.